载脂复合水凝胶传输系统的构建及其对生物活性脂质的保护和释放

Previous studies indicate that the oxidation of algae oil in simulated GI tract is significant. Specifically, the TBARS after small intestinal digestion is ~10 fold greater than that in initial. There is currently a lack of effective delivery systems available to the food industry to encapsulate, protect and deliver lipophilic bioactive components. Part of my previous studies also has shown that some food proteins and polysaccharides possess antioxidative ability to prevent lipophilic bioactive components from being oxidized in vitro. Therefore, protein owning antioxidative ability will be selected to emulsify algae oil forming lipid particles（O/W1）. Then, the protein will also be chose to form water-in-water (W2/W1) hydrogel through thermodynamic incompatibility method when combined with one polysaccharides solution. Lastly, the complex hydrogel （O/W1/W1）encapsulating algae oil will be created by incorporating lipid particles into protein-rich phase of hydrogel through shearing and gelling agent. The protection of algae oil degradation and the release of algae oil in GI tract will be accessed in vitro, in simulated GI tract and in animal studies. It is anticipated that the final complex hydrogel can not only protect the encapsulated algae oil from chemical degradation in vitro and in vivo, but also promote the release of algae oil in small intestinal. The results will also elucidate the structural design principles and mechanisms that govern the formation of complex hydrogel with desired characteristics, which will in turn demonstrate the efficacy of these complex hydrogels to be adapted in food industry for functional food products development.

前期研究发现多不饱和脂肪酸传输系统在模拟人体消化时氧化显著，经体外消化后TBARS是消化初期的10倍。而食品工业正缺乏有效包埋、保护和传递该类生物活性脂质的传输系统。之前研究还发现某些食品蛋白质和多糖能保护活性脂质，但仅限于体外化学稳定性。因此，本项目首先拟利用具备抗氧化活性的蛋白质乳化海藻油制备载脂微粒(O/W1)；再利用该蛋白质与多糖在特定组成下因热力学不稳定相分离制备富蛋白水凝胶(W2/W1)；最后通过机械剪切和特定成胶方法将载脂微粒整合入水凝胶富蛋白相，最终制备复合水凝胶(O/W1/W1)传输系统；通过体外消化、氧化及动物实验筛选保护海藻油降解的复合水凝胶组成。通过本项目的深入研究，有望获得兼具防止海藻油体内外氧化和在消化系统释放的全新食品级传输系统，并揭示复合水凝胶能全面防止多不饱和脂肪酸在体内外氧化的结构基础和作用机制，为食品工业开发全面保护生物活性脂质的功能食品提供理论依据。

长链多不饱和脂肪酸作物生物活性脂质，日常摄入能改善人体健康，然后其易于在食品运输流通环节及被人体食用后被氧化并生成致癌性高级氧化产物。本项目的主要研究内容是构建负载海藻油的载脂颗粒及复合凝胶体系，揭示组成、大小和电荷等性能对凝胶系统的影响，并对载脂颗粒及复合凝胶中海藻油体外氧化稳定性进行了系统评价，最后建立了复合凝胶结构组成-海藻油稳定性关系，获得复合凝胶组成影响多不饱和脂肪酸氧化降解的变化规律。研究表面部分食品级表面活性剂将促进载脂颗粒的体外氧化，磷脂及溶血卵磷脂因其内源性天然抗氧化剂的存在，能有效防止载脂颗粒的物理化学稳定性；此外，水溶性抗氧化剂葡萄籽提取物及抗坏血酸的添加能有效阻止海藻油载脂颗粒脂肪氧化；低浓度单甘油酯（5%）能形成凝胶性能优异的非水复合凝胶系统，而在含水（5%）凝胶系统中，则需要20%以形成相同性能的凝胶；成胶剂浓度的增加能显著延长复合凝胶的氧化稳定性，葡萄籽提取物能有效保护复合凝胶的化学稳定性；体外消化实验表面高浓度（20%）成胶剂能有限保护生物活性脂质的物理稳定性，然后其消化率及生物利用率最低，同时，经体外消化后化学稳定性最高。添加金属螯合剂（EDTA）能有效防止复合凝胶的化学稳定性。